Jonathan Joseph caused trouble against Fiji and in the Six Nations but missed the defeat to Wales through injury.
Photograph: Colorsport/Corbis

It is not an overstatement to say that Saturday night’s encounter between England and Australia is the most important pool match in World Cup history. The hosts of the biggest of all the tournaments will be knocked out if they lose. If a hefty part of the fallout will settle over Twickenham, it will also be scattered wide and I doubt we would again see a group containing three of the leading teams in the rankings.

Never before has the host nation failed to qualify for the quarter-finals. France had to beat Ireland in their group in 2007 after losing to Argentina, but the Irish were all over the place that year. It is more likely to happen at Twickenham because Australia are a team on the way up, and England are under the most formidable pressure, fully aware of the consequences of defeat.

England’s departure would run the risk of puncturing interest in the tournament, with the roadshow ending at the start of the knockout stage. The event will then become confined to London and Cardiff, taking the heat out of some of the passion, and the broadcasters may find a few viewers going elsewhere. However, the show will go on and it is not as if England, tangled up in hype, have brought much to the playing field so far.

It will have been a week unlike any other experienced by the England players and they will have to be at their best mentally against opponents who are quick to exploit weakness. England didn’t play against Wales or make things happen, but it looked as if they would still get over the line when a poor decision late in the game put them in a scrape they have 80 minutes to get right.

They have been hurting and embarrassed since the final whistle against Wales, backs pressed firmly against the wall. For quality teams, it is the perfect recipe for a positive response. Stuart Lancaster’s job will to be to ensure total clarity on the gameplan; he will not need to say anything else – the result against Wales will provide massive focus and motivation. Every team will lose, but their true character is shown in the next match: when I was coaching the All Blacks, I knew that a defeat would galvanise a high-quality performance in the next game. I’m sure England will also be ready but the question is whether this England team are good enough.

They are not the England of 2003: they do not have a leader of Martin Johnson’s stature, a general with Jonny Wilkinson’s astuteness or players of the calibre of Jason Robinson, Will Greenwood, Lawrence Dallaglio, Richard Hill and Phil Vickery.

They lack the self-belief that comes with experience and success, slipping up in one match in each of the last four Six Nations. At the start of the tournament, only three players had reached 50 caps, a far fewer number than their rivals in the group, Wales and Australia. How many of Saturday’s lineup would have got into that 2003 side?

I can see England beating Australia because they have home advantage in a game that will have massive consequences for them if they lose and the Wallabies, who will have another chance against Wales next week, are a bit undercooked, with their starting lineup having played once in six weeks.

England were the best attacking team in this year’s Six Nations, but we have seen little of that in the World Cup so far. They have Jonathan Joseph back to face Australia and, if fully fit, he should make a difference, but perhaps it says everything about where England are at, that they have come to depend on a player who at the start of the year was the third-choice 13 and was only called on because of injury.

You used to know what you would get with England, a powerful scrum, a strong lineout, breakdown presence, unyielding defence and a deadly goal-kicker. Only the last remains, through the freakishly accurate Owen Farrell, but otherwise they have been inconsistent in the set pieces, they apply little pressure on opposition ball at the breakdown because they lack a specialist No7 and they were badly caught out in defence for Wales’s try. Also, if they kick as aimlessly as they did that night, Israel Folau and his mates will punish them.

A big World Cup contest often comes down to goal-kicking and England have a big advantage, with Australia’s Bernard Foley not yet proven from the tee and as a playmaker. Under Michael Cheika’s guidance the Wallabies are a team that are improving, they won the Rugby Championship. They have addressed the aspect of their game that has undone them so often against England in the past 10 years, the scrum. Having David Pocock and Michael Hooper in their back row may cost them at the lineout but they will put a lot of heat on England at the breakdown. The backs will finish on front-foot ball. How Foley goes is critical for Australia.

Watching Wales play against Fiji five days after beating England – something that in the past, as I well know, would have taken their heads into orbit for a long time – was to see what England lack: a hard-nosed approach, maturity, experience, some world-class players as well as an ability to unearth new ones, like Matthew and Tyler Morgan. In this tournament, where they have devastated by injury, Wales have been both brave and resilient, just what England need to be to beat Australia and make the knockout stages of their own Rugby World Cup.